Glycosaminoglycan (GAGS) biosynthesis has been shown to proceed via the initial synthesis of an acceptor protein containing serine residues, to which xylose, galactose, and glucuronic acid are added to form the linkage region between core protein and polysaccharides chain. Elongation then proceeds by the addition of alternating N-acetylated glucosamine and hexuronic acid residues. Sulfation occurs as the polysaccharide chain is being formed. Glucocorticoids inhibit glycosaminoglycan biosynthesis in embryonic chick cartilage. The inhibition of GAGS biosynthesis by glucocorticoids in embryonic chick cartilage is greater than that observed for protein, DNA, or collagen biosynthesis. The exact site of this inhibition has not been determined. We propose to study the effect of glucocorticoids on the acceptor protein, the specific transferases necessary for forming the linkage region of glycosaminoglycans as well as the polymerase enzymes and the sulfotransferase enzymes using both endogenous and exogenous acceptors. Should we have decreased activity using exogenous acceptors this would suggest that cortisol may inhibit the acceptor protein rather than inhibit the transferase enzyme. Glucocorticoid receptors have not been demonstrated in cartilage. We plan to study the presence or absence of glucocorticoid receptors in embryonic chick cartilage as a function of age and maturation.